An unusual coalition of U.S. political advocacy and religious groups has filed suit contesting the legality of the government's surveillance of Americans' telephone records.

The coalition, represented by a digital rights advocacy group called the Electronic Frontier Foundation, filed the lawsuit Tuesday. It claims the spying by the country's clandestine National Security Agency is "an illegal and unconstitutional program of dragnet electronic surveillance."

The lawsuit is the sixth filed against the government seeking to end its vast collection of telephone and Internet records in the aftermath of former U.S. intelligence contractor Edward Snowden leaking details of two secret NSA surveillance programs last month. The NSA collects what it calls "metadata" about the phone calls - the phone numbers Americans are calling and the length of the calls.

The 30-year-old Snowden fled first to Hong Kong, and then, after the United States accused him of espionage, flew to Russia. He is now encamped for a fourth week in a transit zone of a Moscow airport.

Russian lawyer Anatoly Kucherena said Snowden applied Tuesday for temporary asylum in Russia, even though he still wants to eventually travel to Latin America, where leftist governments in Venezuela, Bolivia and Nicaragua have offered him asylum. But Snowden is blocked from leaving Moscow as the U.S. has revoked his passport.

Russian President Vladimir Putin said he does not know how the fugitive's case will play out. He said the U.S. "frightened other countries" into not accepting Snowden.

Putin said Snowden's case is "in limbo right now," but that he expects he will leave for another country "as soon as he has an opportunity to move elsewhere."

The Russian leader has rejected the U.S. request to extradite Snowden to stand trial on the espionage charges. But with Snowden seeking Russian asylum, Washington renewed its bid for his return.

The White House said Snowden is not a human rights activist or dissident, and that he is accused in the "leaking of classified information."